The Journal of Supercomputing
https://doi.org/10.1007/s11227-020-03213-1
A survey on security challenges in cloud computing: issues,
threats, and solutions
Hamed Tabrizchi1 · Marjan Kuchaki Rafsanjani1
© Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract
Cloud computing has gained huge attention over the past decades because of continuously increasing demands. There are several advantages to organizations moving
toward cloud-based data storage solutions. These include simplified IT infrastructure and management, remote access from effectively anywhere in the world with a
stable Internet connection and the cost efficiencies that cloud computing can bring.
The associated security and privacy challenges in cloud require further exploration.
Researchers from academia, industry, and standards organizations have provided
potential solutions to these challenges in the previously published studies. The narrative review presented in this survey provides cloud security issues and requirements,
identified threats, and known vulnerabilities. In fact, this work aims to analyze the
different components of cloud computing as well as present security and privacy
problems that these systems face. Moreover, this work presents new classification of
recent security solutions that exist in this area. Additionally, this survey introduced
various types of security threats which are threatening cloud computing services and
also discussed open issues and propose future directions. This paper will focus and
explore a detailed knowledge about the security challenges that are faced by cloud
entities such as cloud service provider, the data owner, and cloud user.
Keywords Cloud computing · Security · Threats · Vulnerabilities · Data protection
1 Introduction
Large rooms and the huge amounts of electricity play an important role in the history of the technology so that they are widely used to get only a little processing
output. In the last decades, small and more efficient computers have gradually taken
the place of huge (in some cases, room-size) computers. In recent years, the demand
* Marjan Kuchaki Rafsanjani
kuchaki@uk.ac.ir
1
Department of Computer Science, Faculty of Mathematics and Computer, Shahid Bahonar
University of Kerman, Kerman, Iran
13
Vol.:(0123456789)
H. Tabrizchi, M. Kuchaki Rafsanjani
for data has dramatically raised and the number of online users has increased behind
belief. Also, traditional computing infrastructure has become expensive and difficult
to be managed so that accessing data has become impossible by traditional computing anywhere and at any time. Therefore, the external storage system has turned out
to be a necessity for saving data. That traditional computing is now unable to handle
the increased number of online users on networking sites, social networking, multimedia broadcasting, etc. Since global Internet usage has dramatically grown step by
step, the volume of the uses and availability of services led to a new concept called
cloud computing. Figure 1 indicates the progress that the computing infrastructure
and platforms are provisioned.
Cloud computing has brought a lot of benefits like many other technological services. For instance, it made it possible to store a large amount of data and various
services. Furthermore, this platform solved the problem of limited resources and
reduced the cost of services by sharing valuable resources among multiple users.
Resource reliability and performance require the platform to be robust against security threats [1]. In recent years, cloud computing has become one of the most significant topics in security researches. These researches include data storage security, network security, and software security. The National Institute of Standards
and Technology (NIST) defines the cloud computing as [2], “a model for enabling
convenient, resource pooling, ubiquitous, on-demand access which can be easily
delivered with different types of service provider interaction.” The procedure of
cloud computing follows Pay as You Go (PAYG), which the customers only pay the
services they use. PAYG model provides customers with the ability to customize
software, storage, development platform, and computing resources according to the
customer or end-user demands. These benefits are the reason that the research community has dedicated many efforts to this state-of-the-art concept [3].
The virtualization technique has increased the availability of the resources for the
end users. The manageability, scalability, and availability are the main attributes of
cloud computing. In fact, these techniques combine the available resources in a network by splitting up the available bandwidth into separate and distinguished channels in order to assign to a specific server or device or stay unassigned totally [4].
Furthermore, it provides demand service, elasticity, and stability very economically.
Mainframe
Computing
Aforementioned
core memory,
mass-storage
devices, computer
graphics systems
(for plotting the
aircraft)
60s, 70s
SMP/open
Systems
Pool of
homogeneous
processors,
independent
administered
software
Distributed
Computing
web-based
application,
multitier
architecture
Grid
Computing
Providing
virtualization of
distributed
computing
resources
Cloud
Computing
Late 90s
Early 2000
Late 2000
80s,90s
Fig. 1 The computing architecture evolution
13
IaaS,
PaaS,
SaaS
A survey on security challenges in cloud computing: issues,…
Fundamentally, cloud computing provides three different models of service delivery, called software-as-a-service (SaaS), infrastructure-as-a-service (IaaS), and platform-as-a-service (PaaS). SaaS model emphasizes on access management tasks in
applications like policy controls. For instance, a person is only allowed to download
certain information from applications. In this way, multiple end users benefit from a
single instance of the service. Today, companies like Google, Microsoft Office 365,
Dropbox, etc., offer SaaS. In PaaS, a layer of the development environment is used
as a service and other higher level of service can be built. In the PaaS model, the
customer creates their own applications running on the provider’s infrastructure. In
fact, PaaS offers a combination of OS and application servers like Microsoft Azure,
Google App Engine, LAMP platform (Linux, Apache, MySQL, and PHP), etc. It
is worth noting that one of the main focuses of the PaaS model is data protection.
This becomes notably important in the case of storage as a service. It should be
considered that this model should be able to encrypt data while storing them on a
third-party platform and should be aware of the regulatory issues that may impress
data availability in different geographies. IaaS offers computing capabilities and
essential storage as standardized services across the network. The inherent strategy
of virtualization is to arrange independent virtual machines (VM) and isolate them
from both the underlying hardware and other VMs. IaaS also emphasizes on security
fields like firewall, intrusion detection, prevention (IDS/IPS), and virtual machine
monitor. Cloud computing is considerably and rapidly growing and more and more
organizations adopted cloud technology every day. However, there are several parallel security issues that should be taken care of. Organizations pick out some secure
infrastructures when transmitting their data to remote destinations. In this way, each
customer would typically use his own software on the infrastructure [5]. Google
Compute Engine (GCE), Amazon Web Services (AWS), Cisco Metapod, and Microsoft Azure are among the most important examples of IaaS.
Cloud computing has many aspects including cloud development model that provides a certain type of cloud environment, mainly distinguished by its size, ownership, and accessibility. In fact, cloud computing is empowered by sharing resources
among individual devices or local servers. The purpose and nature of the cloud are
associated with deployment model. Deployment model includes three types, namely
public cloud, private cloud, and hybrid cloud [6].
In the private cloud, cloud computing deal with the data center of an organization. In this model, resources are allocated to a single organization or multiple ones
and work inter-functionally. For this reason, infrastructure is owned and operated by
the same organization in this type of cloud. Also, customer and vendor relationship
identification and security risk detection are much easier. In the second model, government, business or academies own and operate a public cloud. Also, organizations
could provide open access over the Internet or another portal in this model. In this
type of cloud, many challenges appear in the field of resource location and ownership detection. Furthermore, it is very complicated and difficult to protect resources
against various types of intrusions and attacks. However, the third deployment
model, the hybrid cloud, is the best one in terms of advantages. This model offers
private cloud associated with one or more external cloud services, while the data
and application are bound together and managed centrally. It is worth noting that
13
H. Tabrizchi, M. Kuchaki Rafsanjani
hybrid cloud security is more reliable than the public cloud’s if the entities access
across the Internet. However, each of deployment models has their specific advantages and disadvantages. In fact, each deployment model has a specific advantage
and disadvantage with regard to user experience. The private cloud provides complete control over the user experience. However, in some cases, the public cloud has
no control over the user experience and hybrid cloud admit control over the user
experience relies on the agreement have placed with the consumer [7]. In addition,
Table 1 illustrates the advantages and disadvantages of public clouds, private cloud,
and hybrid cloud.
However, there is a shared responsibility security model behind all services provided by cloud computing. Both the provider and cloud consumer have a role in
the security of cloud-resident infrastructure and cloud-delivered applications. The
responsibility for security is different in each delivery model. In some services, the
customer is responsible for data security like user access and identity management
in any case of delivery models (IaaS, PaaS, and SaaS) as shown in Fig. 2.
To release the security patches or updates, they should be comprehensively
tested, repackaged, and stored in the repository. However, customers have some
responsibilities like collaborating with provider regarding to system maintenance. In
this regard, they should install patches on the operating system (OS) and application
stack and act the role of the system administrator in the cloud by patching and updating operating systems and various applications [8]. Other customer responsibilities
are user account creation management, provisioning, and destruction, server-level
account authentication mechanisms, password policies, etc. Customers’ data activity
can be monitored using the logs automatically delivered to their accounts. However,
both the cloud provider and cloud customer are responsible for different aspects of
the system and both must take some actions to secure the service properly.
According to Oracle and KPMG Cloud Threat Report (2018) [9], only 43% of
respondents were able to correctly recognize the most common IaaS shared responsibility security model. Organizations should employ various network security
controls like physical and VM-based firewalls, intrusion detection and prevention systems, and gateways as well as the purposeful workload and cloud application controls. Also, 66% of respondents said they faced a cyber security incident
Table 1 The pros and cons of public, private, and hybrid clouds
Cloud development models
Advantages
Disadvantages
Public cloud
Scalability and reliability with on-demand
resources
Can be unreliable
Easy to use
Less secure
Organization-specific
More costly
Customizable
Requires IT expertise
Flexible infrastructure
Lack of visibility
Cost controls
Potential challenges in
application and data
integration
Private cloud
Hybrid cloud
Faster speeds
13
A survey on security challenges in cloud computing: issues,…
User
Front end
storage
Communication
Cloud software infrastructure
Kernel(OS/Apps)
Provider
IaaS
Cloud software environment
Computational
resources
Other mechanisms
PaaS
Cloud (web) application
Management access
SaaS
Services and APIs
Network
Hardware
Facilities
Fig. 2 Configuration of cloud delivery model [2]
affecting their business operations over the past 2 years. These effects were standard
business operation disruption, service providing disruption, employee productivity loss, and delays in IT projects. In fact, cloud companies have provided a lot of
attributions like global availability of high-performance services, support of a large
number of services, storing a large amount of data [10].
The rest of the paper is organized as follows. A background of main security services and the main known techniques to fulfill each service is presented in
Sect. 2. In Sect. 3, the main cloud security issues and challenges are classified and
described. Also, we present our new classification of security solutions in this section. In Sect. 4, different security threats threatening cloud computing services are
introduced. Then, in Sect. 5, the importance of cloud security issues in the future is
discussed. Finally, conclusions are presented in Sect. 6.
1.1 Contributions on this survey
Given the undeniable need for computation and storage resources in today’s world,
many new technologies have decided to consider cloud computing as the main
computing or storage component. However, this popular phenomenon suffers from
various security challenges and vulnerabilities. It is a vivid fact that cloud environment faces many threats. For this reason, using this phenomenon requires sufficient knowledge and the best possible solution to deal with each of these threats..
In the current study, several studies are reviewed and some of them having more
importance will be discussed. In fact, this work deals with the expression of security
issues, challenges, and threats in cloud computing.
The main contributions of this work can be summarized as follows:
13
H. Tabrizchi, M. Kuchaki Rafsanjani
• The basic concepts of cloud computing and all entities associated with the archi-
tecture of cloud computing systems are introduced.
• We provide a new classification of cloud security issues and challenges based on
the security state of cloud environments into five categories.
• We provide an overview of the cloud security threats model, recent computing
threat based on the STRIDE threat model and also categorize attacks based on
the OWASP attack classification.
2 Literature review
2.1 Background
The Background section discusses issues such as data security preliminaries and
presents some information about the architecture of cloud computing systems.
2.1.1 Security service
Security includes all the approaches aiming to preserve, restore, and guarantee the
protection of information in computer systems against various threats. In fact, the
security services implemented by security mechanisms execute security policies. As
shown in Table 2, the security of computer networks and information systems is
provided by services like integrity, confidentiality, authentication, non-repudiation,
and availability [11].
• Confidentiality ensures that information is not disclosed and available to unau-
•
•
•
•
thorized individuals, entities, or processes. In fact, data should be sent (and
received) data without being accessed by unauthorized entities during the transmission. Data encryption is a good way to realize confidentiality. Encryption can
be accomplished by symmetric or asymmetric key paradigm.
Integrity ensures the data received by an authorized person is same as the sent
data without any modification. In other words, it guarantees that data have not
been modified by a third party (intentionally or accidentally). When an intrusion occurs, the connection is dropped and the invalid information transmission
is canceled.
Availability ensures the availability of services for rightful users and makes data
accessible and useable upon demand by an authorized entity. For instance, when
a distributed denial-of-service (DDoS) attack occurs in a system, it will lose its
ability to transfer data.
Authentication confirms the identity of the information transmitter and recipient.
In fact, the integrity and confidentiality of information are meaningful just when
the identities of senders and receivers are properly verified.
Non-repudiation ensures that the actions taken cannot be denied by senders or
receivers. There are two kinds of repudiations—source repudiation and destination repudiation. In the former, sender or receiver cannot deny the transmission
of a message, and in the latter, they cannot deny the delivery of a message.
13
Symmetric cryptographic mechanisms (AES, CBC, etc.) asymmetric mechanisms
(RSA, DSA, etc.), post-quantum cryptography
Data encryption (cryptography, quantum cryptography), secure
sockets layer (SSL)
Hash functions, message signature, message authentication code
Intrusion detection and prevention systems, firewalls, packet filters Signature-based intrusion detection, statistical anomaly-based intrusion detection,
etc.
Digital signature, secure sockets layer (SSL), endorsing certificate HMAC, CBC-MAC, ECDSA, certified signatures, SSL certificate
Digital signatures, notary, public, and private blockchains
Confidentiality
Integrity
Availability
Authentication
Non-repudiation
Email tracking, capturing unique biometric information and other data about the
sender or signer
Hash functions (SHA-256, MD5, etc.), message authentication codes (HMAC),
public blockchains [ethereum (platform)]
Some examples
Security services Security mechanisms
Table 2 Security services and mechanisms
A survey on security challenges in cloud computing: issues,…
13
H. Tabrizchi, M. Kuchaki Rafsanjani
2.1.2 Cloud configuration
For a better understanding of security issues, we should first understand the cloud
configuration we have discussed in the following paragraphs. A cloud company is
made of the resources dedicated to demands. According to NITS, cloud computing
configuration has five major actors listed in the following table [12, 13]. The classification focuses on cloud customer’s and cloud provider’s threats and risk-awareness.
The actors mentioned in Table 3 are the entities taking part in a process or transaction and/or playing a role in cloud computing.
2.1.2.1 Cloud consumer A cloud consumer is a person or organization that gets
some services from a cloud provider. In fact, a cloud consumer can opt the most
fitting services by scrutinizing the services offered by cloud providers and closing a
contract. To close this contract, a cloud consumer has to determine the technical performance by signing a service-level agreement (SLA) with a cloud provider. SLAs
(as an agreement) cover things like consistency of the quality of services, security,
prevention, and performance failure. However, a cloud consumer is able to choose
providers offering more favorable services and better prices.
2.1.2.2 Cloud provider A cloud provider is a person or organization making a service available to a cloud consumer. The cloud provider organize and arrange cloud
software by acquiring and managing the cloud infrastructure. In SaaS, the cloud provider provides services at expected service levels through deploying, configuring,
maintaining, and updating the software applications. According to the limited administrative applications of cloud, most of the managing and controlling responsibilities
in the infrastructure and application are on SaaS provider’s shoulders. In PaaS, the
cloud provider manages the computing infrastructure of the platform and the components of the platform (such as runtime software, database, or other middleware
components) are provided by cloud software. In IaaS, the cloud provider acquires the
physical computing resources including the networks, storages, servers, and hosting
infrastructure.
Table 3 Different actors in cloud computing
Actor
Definition
Cloud consumer A person or organization that maintains a business relationship with, and uses service
from, cloud providers
Cloud provider
A person, organization, or entity responsible for making a service available to interested parties
Cloud auditor
A party that can conduct an independent assessment of cloud services, information
system operations, performance and security of the cloud implementation
Cloud broker
An entity that manages the use, performance and delivery of cloud services, and negotiates relationships between cloud providers and cloud consumers
Cloud carrier
An intermediary that provides connectivity and transport of cloud services from cloud
providers to cloud consumers
13
A survey on security challenges in cloud computing: issues,…
2.1.2.3 Cloud auditor A cloud auditor is responsible to examine the cloud services
independently. The auditor checks the conformance to standards by reviewing various objective evidence. The services offered by cloud providers can be assessed by
cloud auditor regarding their privacy impacts, security controls, performance, etc.
2.1.2.4 Cloud broker As the integration of cloud services is too complicated to be
managed by cloud consumers, they acquire the cloud services via a cloud broker
instead of contacting with cloud provider directly. In fact, the cloud broker is responsible for managing the usage, performance, and delivery of cloud services as well
as the relationships among the cloud consumers and cloud providers. The services
offered by cloud brokers can be categorized into three categories:
• Service intermediation A cloud broker can enhance a certain service by improv-
ing some specific capabilities and providing value-added services to cloud consumers. These improvements include cloud services’ access management, performance reporting, identity management, enhanced security, etc.
• Service aggregation refers to the actions taken by a cloud broker to combine or
merge multiple services into one or more new services. In fact, the cloud broker
integrates data and plays the role of a bridge between the cloud consumer and
multiple cloud providers.
• Service arbitrage performs like service aggregation, but services are not aggregated to be fixed. In fact, service arbitrage gives the broker the flexibility to pick
services from several agencies. For example, a cloud broker can use a creditscoring service to assess and select the best agency.
2.1.2.5 Cloud carrier A cloud carrier intermediates between cloud consumer and
cloud provider to deliver cloud services. Cloud carriers get access to consumers
through the network and other access devices. As discussed earlier, by establishing
SLAs with a cloud carrier, the cloud provider can bring services consistent with the
SLAs to cloud consumers. Furthermore, cloud carrier is responsible for dedicating
secured connections to cloud consumer and the cloud provider.
In Fig. 3, the diagram indicates an overview of the NIST cloud computing configuration [13] including its major actors, their activities and functions in cloud computing. According to the mentioned contents, the diagram characterizes the requirements, characteristics, and standards of cloud computing.
2.2 Existing review papers on security challenges in cloud computing
Cloud computing is an emerging computing paradigm that brings great deals of
new challenges for data security, access control, etc. [14]. During the last decade,
a lot of survey papers focus on the security challenges in cloud computing. Moreover, it is undeniable that most of the presented reviewed papers play a valuable
13
H. Tabrizchi, M. Kuchaki Rafsanjani
role in cloud security issues and these noticeable reviewed works had been a lot
of valuable and comprehensive research in this area.
Sgandurra and Lupu [15] have presented a taxonomy of attacks in virtualized
systems in terms of the target at the different levels, the source and goals of the
attackers. In fact, they aim to illustrate the evolution of the threats, related security, and trust assumptions in virtualized systems at the different layers such as
hardware, OS, and application.
Kaur and Singh [16] presented a review of cloud computing security issues.
This work has discussed the issues related to data location, storage, security,
availability, and integrity. In fact, this review focuses on one of the significant
security concerns, although it is vital to note that the authors only address security issues without discussing the possible solutions.
Kumar et al. [17] have demonstrated diverse kinds of data security issues in
cloud computing and also presented an approach to overcome security issues in a
multi-tenant environment. In fact, this paper completely focuses on data security
issues and also presents methods to protect the data and its privacy.
Khalil et al. [18] present a review study of cloud computing security and privacy concerns. In this work, various types of known security threats and attacks
are classified and also different kinds of cloud vulnerabilities identified. Moreover, this review work investigates the drawbacks of the current solutions and discuss future security perspectives.
Bashir and Haider [19] provide a review study in order to indicate the most
vulnerable security threats in cloud computing. In addition, this review work considers both end users’ and vendors’ key security threats associated with cloud
computing by providing analysis related to the different security models and
tools.
Ryan [20] present a survey with vital research directions such as protecting
data method that aims to keep safe data from a cloud infrastructure provider.
Moreover, this work describes a browser key translation method that allows a
software-as-a-service application to provide confidentiality service.
Table 4 indicates a summary of the contributions of some of the recent surveys
reviewing security challenges, attacks, and threats in the cloud environments.
One of the long-dreamed vision of computing as a utility, where users can
remotely store their data, is cloud computing which provides high-quality services from a shared pool of configurable computing resources [21]. Due to the
fact that the majority of technologies related to cloud phenomenon witnessed
many signs of progress in today’s world, security risks become more advanced
and new challenges arise. For this reason, comprehensive research is needed
along with identifying potential challenges and providing new solutions. In addition, the majority of the mentioned surveys have discussed the aspect of security issues about clouds without considering a comprehensive review of issues,
challenges, and threats in the cloud environment. We have focused on all detail
related to cloud security and challenges and discuss existing solutions as much as
possible.
13
Cloud data storage
2015
2018
2014
2011
2013
Kaur and Singh [16]
Kumar et al. [17]
Khalil et al. [18]
Bashir and Haider [19]
Ryan [20]
Present the state-of-the-art practices to control the vulnerabilities, threats, and
attacks
Classify known security threats and attacks
Identify cloud vulnerabilities
Describes cloud computing models such as the deployment models and the
service delivery models
Proposes methods to overcome the security issues
Explores the diverse data security issues in a multi-tenant environment
Focused on data location, storage, security, availability, and integrity
Focused on hardware, virtualization, OS, and application
Categorize threat models, security and trust assumptions, and attacks
Evolution of the threats and of the related security and trust assumptions
Remarks
Cloud security challenge and a survey of solutions
Explore trusted hardware used to protect cloud-based data
Describe a method in which in-browser key translation allows a software-as-aservice application to run with confidentiality from the service provider
Explain some difficulties with using fully homomorphic encryption for cloud
computing applications
Identify vulnerable security threats in cloud computing
Identification of security threats in cloud computing Focused on both end users and vendors key security threats associated with cloud
computing
Cloud security and privacy
Cloud data security issues
Taxonomy of attacks
Years Objective
Sgandurra and Lupu [15] 2016
References
Table 4 Summary of existing surveys
A survey on security challenges in cloud computing: issues,…
13
H. Tabrizchi, M. Kuchaki Rafsanjani
3 Cloud security issues and challenges
Although cloud computing has brought a variety of beneficial services, it also
involves many security threats and challenges. Since a lot of information is transferred through the network and stored in specific resources in the cloud, there are
many vulnerabilities that can be exploited by malicious actors. In this section, we
discuss the security state of cloud environments classified into five categories [22,
23]. It should be noted that each subsection of this section is allocated to a common
security property. As illustrated in Fig. 4, cloud security issues can be categorized
into the following five categories: security policies, user-oriented security, data storage security, application security, and network security.
3.1 Security policies
Security policies include the standards necessary to prevent attacks by taking precautionary measures. These standards should secure the working environment in
cloud without compromising its performance and reliability [7, 24]. Security policies work based on regulatory authorities and involve various service-level agreements (SLAs), client management issues, and antecedent trust.
3.1.1 Service‑level agreement (SLA)
A service-level agreement is associated with the relationship between customers and
providers and includes both. Service providers are expected SLAs to manage customer expectations. In fact, SLAs establish the circumstances under which providers are not responsible for outages or performance issues. Also, SLAs represent the
Fig. 3 NIST cloud computing configuration [13]
13
A survey on security challenges in cloud computing: issues,…
performance characteristics of services which can be used for comparison purposes.
However, SLA cannot guarantee that a particular service will be achieved. In other
words, SLA does not eliminate the risk of choosing a bad service and is not able to
turn a bad service into a good one. In general, SLA consists of a statement of objections and a list of the services covered by the agreement. Also, at the same time, it
determines the responsibilities of the service provider and customer under the SLA.
SLA specifies availability, usage statistics, service provider response time, and specific performance benchmarks that will be provided [25].
3.1.2 Client management issue
In recent years, most organizations have attempted to focus on the customer. The
client management issue as one of the most significant concerns in cloud security
has many different aspects including client experiences, client-centric privacy, client
authentication system, and client service-level agreement. These different aspects of
security in cloud business will be discussed in the following paragraphs [26].
3.1.2.1 Client experience (CX) Customers expect their providers to recognize their
special demands, personal conditions, and life difficulties. To offer better services,
providers must know their customers’ needs and deliver customized solutions for
them. The customer experience plays a vital role in cloud. This experience makes
companies able to deliver products and services according to customer’s values. For
example, there are some advantages of cloud that are derived from a user’s search
history and its connection with the provider. In recent years, the cloud-based services
have improved the customer experiences in the market so that many companies are
in trouble because of the lack of cloud-based customer system, whereas choosing a
secure cloud provider company will be difficult for customers with experiences in
security areas.
3.1.2.2 Client authentication Ensures that users get access to a server or remote
computer by presenting a digital certificate. This digital certificate acts as a “Digital
ID,” and its function is to cryptographically bind a customer and employee’s identities. The digital certificate makes cloud resources able to control accesses and preCloud security issues classification
Application
Network
Security policies
User-oriented security
Data storage
Service level agreement
Authentication
Data warehouse
Operating systems
Client management issue
Authorization
CIA Tired
Front end/ Back end
Intrusion detection system
Antecedent trust
Identity and access management
Malware
Application vulnerabilities
Firewalls
Intrusion prevention system
Meta data
Fig. 4 Different categories of cloud security issues
13
H. Tabrizchi, M. Kuchaki Rafsanjani
vents non-rightful users to get access to cloud services. Users should be able to get
access to their applications from anywhere and any device like cell phones, tablets,
laptops, smart televisions, etc.; however, it is a challenge for cloud service providers
to guarantee that only rightful users get access to their services. Nevertheless, it is
worth noting that there are various authentication threats and attacks in cloud environment including password discovery attacks, cookies reply attack, credential theft
(for instance, phishing or social engineering), man in the middle attack, and many
other ones [27].
3.1.2.3 Client‑centric privacy Nowadays, the most significant vulnerabilities in the
cloud appear when privacy is lost and data leakage arises [28]. In fact, data processing by provider causes this challenge and compromises client-centric privacy. This
challenge is a critical barrier to adapt cloud services. For example, when a user submitted the data into the cloud machine for processing, it has no control on processing
procedure. In fact, the users have not any knowledge about where their data reside
and are stored and used. For example, the service provider is able to share the sensitive data with unallowable individuals without user permission leading to privacy
loss and data leakage. As a result, we need a client-centric solution to solve this
challenge. This solution should make the users able to control their submitted data.
Therefore, a client-centric approach is required to solve this problem. This problem
can cause many issues like security, privacy, trust, and customer relationship management (CRM) issues.
3.1.2.4 Service‑level management As mentioned, SLA is used to provide the agreements and their costs. In fact, service-level management (SLM) is the process in
which the benchmarks for level of service are arranged. This process measures the
performance compliance expected by customer. Also, in an SLM process, different
services are structurally defined and service levels needed to maintain business processes are agreed upon. The definition structure should contain the security responsibilities of both internal and external service providers and customers. In this regard,
service-level management covers the role and define the organization structure.
3.1.3 Antecedent trust
Trust is one of most important facilitators to make business relationships strong.
Since trust has received a pale attention in cloud computing, as a result, the lack of
trust understanding in cloud services has caused huge challenges for the adoption of
cloud computing. This challenge has created a gap between adoption and innovation
and caused the cloud computing consumers not to fully trust this new way of computing. To fill this gap, the trust issue related to could computing should be recognized from both technological and business perspectives [29, 30].
3.1.3.1 Human factor At the first glance, reinforcing the security of the cloud
provides a secure infrastructure for information. However, considering the human
13
A survey on security challenges in cloud computing: issues,…
factor of the cloud security is a necessity for organizations. To characterize the
human role in the security aspect of the cloud, it should be noted that human is
able to create various innovations and solve all the problems. In cloud systems,
human access level to the system is different, so that an employee or costumer with
administrator access level can play a critical role in saving or damaging system
security. To fix security threats and eliminate vulnerabilities, in addition to technological defects, human mistakes, and behaviors should definitely be considered.
With more emphasis on human behavior, a vulnerability pattern (such as social
engineering) can be found. Then, social engineering attacks will be monitored and
studied in more detail.
3.1.3.2 Digital forensics The more the network applications, the more the digital
crimes. Digital forensics play a vital role in protecting and restoring operational data.
In other words, digital forensics is the process used to uncover and interpret electronic data. With increased number of users in the digital worlds, it is more likely
that non-rightful malicious users exploit the cloud services. Furthermore, this issue
is propagated to wider bounds when costumers bring their own accessible devices
including PC Windows, MACs, iPhones, and Android smart phones. However, the
digital forensics have encountered many challenges including the wider range and
increased number of devices operating in the cloud have made it more difficult to
archive and encrypt data from different operating systems in different platforms.
3.1.3.3 Costumer trust status According to a recently published report [31], many
organizations are concerned about their personal and sensitive data kept by companies. They are worry that these companies can use the data for purposes other than
what they collected for. According to this report, although 93% of organizations use
cloud services at the moment, only 23% of them completely trust public clouds to
keep their data secure. When moving to IaaS, the most important desire of related
authorities is to have stable security controls providing integrated security with central management across all cloud and traditional data center infrastructure. However,
although the trust in public cloud services continues to improve year by year, the
reports published on cloud security topic should always be reviewed.
3.1.3.4 Trust third party (TTP) One of the main concerns of cloud users is about
how their data are used because it is possible that malicious data centers exploit
these data. In this regard, trust third party (TTP) can authenticate, audit, and
authorize the confidential data and protect information against unauthorized malicious people. Therefore, when the third party is discredited, the cloud environment
will be severely threatened and many security properties will be compromised. In
fact, the starting point of the challenge is where users do not know the location the
resource allocated to store their data [32]. Therefore, this problem can be basically
solved by the following steps. First, the data submitted by cloud customers should
be encrypted using symmetric key encryption algorithms. In this step, TTP asks
secret key and holds it to perform data verification or identification tasks. Finally,
the service provider is able to ask secret key and perform the data processing task.
13
H. Tabrizchi, M. Kuchaki Rafsanjani
3.1.3.5 Governance Cloud computing governance as an aspect of information
technology governance presents integrated management with automated performance resolution, balancing resources in a cloud environment. Unfortunately,
many organizations adopt cloud environment without understanding the governance importance in the modern life of IaaS. If this issue is disregarded, the
administrator operations and access security controls will be lost. In summary,
cloud computing governance creates the policies and principles that control the
lifecycle of services offered in the cloud. Governance can solve the problem of
losing administrative operations and access security controls that may be resulted
from the lack of well-established standards. As a result, it is clear that incorrect
governance can lead to weakening financial capabilities of the cloud providers,
complicating the time management to recovery, and increasing the possibility of
data breaches and service terminations [33].
3.2 User‑oriented security
Due to the complexity of usage, cloud computing requires extensive user-oriented
security to make its data and resources secure. In fact, one of the most important
issues in cloud security is that cloud service providers can control the storing and
processing steps of information submitted by users. This aspect of security includes
identification, authentication, authorization, and access management issues.
3.2.1 Authentication
As you know, cloud computing benefits businesses by storing large amount of data
by less cost. Fortunately, as necessity, service providers should guarantee that users
are authenticated by specific methods. This authentication is completely or partly
done by a software. In a cloud environment, a simple authentication mechanism
is not suitable for the costumers accessing and composing services from multiple
cloud providers. The privileged user access is an event happening when these kinds
of accesses have caused an inherent level of risk. However, there are various authentication methods that can be used to solve this problem. Generally, access permission is dedicated when the users present something they individually know, such
as their card number or a password defined by them. In total, these methods can
be divided into two categories, namely physical security authentication mechanisms
and digital security authentication mechanisms [34].
3.2.1.1 Physical security authentication mechanism One of the recent attractions for
organizations is to provide their customers with easy access to their cloud resources
at any time. This can be provided with the help of the cloud data centers centralizing
old servers, networks, and applications that users are able to access them at anytime
and anywhere. In fact, physical security authentication mechanisms such as access
cards and biometrics (including retina recognition, fingerprint recognition, and face
recognition) are used to prevent unauthorized access. In this regard, some certain
13
A survey on security challenges in cloud computing: issues,…
usage and governance policies should be considered with respect to physical security
[35].
3.2.1.2 Digital security authentication mechanisms Similarly, digital authentication
is used when an individual or online entity is honest with the server provider or when
it seems that the mechanism is suitably established [36, 37]. One of the mathematical
schemes that provide verification and authentication of any kind of digital message
is a digital signature. In fact, the name of the digital signature is inspired by handwritten signatures in the physical world. In real life, it is common to use handwritten
signatures on the paper’s messages. In a similar way, a digital signature is a particular
form of procedure that binds a sender entity to the digital data based on cryptography concepts. In other words, the digital signature is a cryptographic value that is
calculated from the data and a secret key known only by the signer. Apart from the
ability to provide non-repudiation of the message, the digital signature also provides
message authentication (he message was created by a known sender) and data integrity (the message was not altered in transit). For example, some of the most common
digital authentication methods in a cloud environment are credentials, secure shell
keys, multi-factor authentication, personal identification number, and single sign-on
(SSO).
Credentials: Credentials work as evidences of authority, entitlements, status, and
access rights. They provide particular users with an evidence to prove that they
are rightful to use resources and services. In fact, taking advantage of credentials
(such as one-time passwords, patterns, and captchas) is a traditional way of securing malicious activities. Since the management overhead of the credentials is high,
it is necessary to add, disable, modify, or remove accounts whenever any user enters
or leaves the service (or organization). On the other hand, when a weak password
recovery mechanism is used, the credential reset vulnerability appears. In this way,
hackers can monitor or manipulate data in the cloud with malicious activities when
the credentials are at the risk of abuse. By encrypting and signing the authentication
server, the credentials help the communication among the clients and terminals. The
asymmetric encryption technology is able to use public and private keys as a personal identification number (PIN). The advantage of using PINs is that they are used
in multiple types of network systems and websites. However, credentials simplify
information privacy management while preventing unauthorized access by abusing lost credit/debit cards or usernames/passwords. In this way, a PIN is responsible
to authenticate the client/terminal for getting access to user data and keys from the
chip.
Single sign‑on: The conventional authentication mechanisms are not always suitable
for remote authentication because a centralized monitoring system is required for
SaaS applications, limiting the software policies. In other words, the existence of
multiple services causes that the cloud customers need multiple login requirements
and make various problems because only a single user may be forced to maintain
a large number of credentials. Because of these reasons, the possible solution is to
13
H. Tabrizchi, M. Kuchaki Rafsanjani
take advantage of single sign-on (SSO) technique. SSO provision provides one password to get access to all applications and services in the cloud environment.
Secure shell (SSH): SSH is a network protocol that provides a secure way to get
access to a remote computer. SSH keys respond to SSH server identification with
public key cryptography or challenge authentication with the SSH. In this regard,
all user file transfers, commands, and authentications are encrypted to protect users
against attacks in the network. The main benefit of SSH key is that the authentication process is accomplished without passing the password over the network. In fact,
SSH can prevent the interception or cracking of the passwords by a person leading
unauthorized access to data and provides a secure channel based on client–server
model by considering the unsecured network in a client–server architecture. However, one of the most critical aspects of SSH is key management. It should be noted
that when the suitable centralized creation, rotation, and elimination of SSH key are
ignored, the system can lose its control on resource access management.
Multi‑factor authentication: Another method to secure digital assets and transactions in the Internet is the multi-factor authentication. This method has many kinds
like One-Time Password (OTP), Captchas, or patterns that all of them are involved
in the secondary authentication mechanism. The multi-factor authentication can recognize the trustworthy users through their information clarification. In fact, the more
the number of the factors used to clarify the user identity, the greater the authentication. It should be noted that with the advent of mobile networks, second-factor
authentication has taken the form of SMS, push notification, and mobile OATH
tokens.
Personal identification number (PIN): A person identification number is a secure
alphanumeric or numeric code that is used to authenticate the access requests. Since
different applications and resources follow various authentication mechanisms, single sign-on can internally save the credentials used for primary authentication and
translate them into the credentials required for a variety of mechanisms. However, to
highlight the advantages of the cloud, it is better that users not specify their credentials whenever they get access to different cloud web services. In this regard, single
sign-on (SSO) can reduce password fatigue from different username and password
combinations.
3.2.2 Authorization
Authorization is a method which gives permission or prevents the access to a particular resource according to an authorized user’s entitlements. In the systems in
which users are permitted to access to the system, a system administrator is specified. According to the fact that a cloud network consists of different service providers, there is a common situation in which a single user is able to access different types of services at the moment, so that each service is provided by a different
service provider and with a different security level. For example, when the user
13
A survey on security challenges in cloud computing: issues,…
authorizes the application, cloud-hosted applications are permitted to be accessible
from outside the application. In this situation, authorization is done by either access
right delegation or access control policies. In fact, through the cloud environment,
the cloud service provider presents and executes access control policies like the services and resources should only be accessed by the authorized users [37, 38]. Some
of the advantages of centralized access mechanisms include securing the sensitive
information and reducing several management and security tasks. However, there
are many authorization mechanisms including MAC, DAC, RBAC, and ABAC. In
addition, Table 5 indicates the advantages and disadvantages of these authorization
mechanisms [39].
3.2.2.1 Mandatory access control (MAC) MAC makes it possible to get access
through the operating system or security kernel. The system manager, its security
policy, and all access control rights determine the usage of resources and their access
policies which cannot be overridden by the end users. Therefore, these policies will
slow who has the authority to access the particular programs and files. MAC is widely
employed in the systems in which the confidentiality is a priority. Although MAC is
a secure way for resource access management, it is less flexible to process the access
rights.
3.2.2.2 Discretionary access control (DAC) DAC mechanism is vice versa, regarding
MAC. As mentioned earlier, MAC policies are determined by user permission while
validation of the username and password in DAC is to specify the access right of each
user. Because data owners exist in DAC, data access policies are supervised by them.
Generally, DAC is more flexible, but less secure compared to MAC.
3.2.2.3 Role‑based access control (RBAC) Role-based access control restricts
system access to authorized users. In RBAC, each role is statically specified by
the system administrator. In fact, access to the computer or network resources is
Table 5 Advantages and disadvantages of these authorization mechanisms
Authorization
mechanisms
Advantages
Disadvantages
MAC
Easy to scale
Limited user functionality
High security
Not flexible
Easy implementation
Does not support dynamic alteration
Flexibility
Requires a high system management
Independence authorization management
Not preferred in a dynamic environment
Separation of duties
Not possible to change access rights
without changing the roles
DAC
RBAC
Hierarchy of roles
Least privilege
ABAC
High flexibility in a distributed and dynamic Require the central database
environment
Central storage for user attributes
High complexity
13
H. Tabrizchi, M. Kuchaki Rafsanjani
mostly controlled by RBAC based on users in an organization. In RBAC, several
parameters are considered to give the permission to the user; including role permission, user–role, and role–role relationship. These roles can be categorized into
two categories, namely application/technical roles and organizational/business
roles. RBAC provides the systems having large number of users and permissions
with appropriate administration security. One of the advantages of RBAC is its
highly secured environment for allocating access permissions. On the other hand,
the main defect of RBAC is that the assigned roles might change over the time,
requiring real-time environment for validation and investigation of changes.
3.2.2.4 Attribute‑based access control (ABAC) ABAC presents a control over the
access where rights are granted to users using the policies combining attributes
together. The polices follow any type of attributes like user attributes, resource
attributes, object attributes, environment attributes, etc. Generally, since roles and
privileges of any individual user are pre-defined in the ABAC mode, it eliminates
many authorization problems, gains an effective regulatory compliance, and provides implementation flexibility [40].
3.2.3 Identity and access management
Identity and access management is a framework consisting of the organizational
policies for managing digital identity at the condition that technology is supported well enough to find the ability for identity management [41]. Also, it is
necessary for identity access management systems to have all the required controls and tends to save and record user login information, manage the enterprise
database of user identities and manage assignments and elimination of access
privileges. In other words, identification and access management system has the
responsibility to prepare a centralized directory service by considering all aspects
of the company’s user base. However, the identity and access management system
is currently unable to directly enhance either profitability or functionality. Therefore, it is very difficult to take funds for these projects. However, with the lake of
impressive identity and access management situation, there would be a huge risk
for organizations’ compliance and overall security.
3.3 Data storage
In physical cloud storage model, data are stored in logical pools. The physical
storages span various servers so that each of them is owned and operated by a
separate hosting company. By taking into account the significant growth in various online applications and multiple Internet devices, data storage and its security over distributed computing environments is a vital issue. In fact, cloud providers should take the responsibility for the data availability and accessibility at
any time [42]. The defects that come about to control the data have caused some
13
A survey on security challenges in cloud computing: issues,…
security issues like warehouses, availability, confidentiality, integrity management (CIA), etc.
3.3.1 Data warehouse
Data warehouses are the huge central repositories of integrated data having disparate sources. In fact, all data collected by enterprises and various operational systems are integrated in physical or logical data warehouses. These data warehouses
use various sources for giving priority on the access and analysis rather than transaction processing [43]. Typically, data warehouse security is an important requirement for implementation and maintenance. It is worth noting that storage security is
a critical aspect of the quality of services (QoS). In this regard, data warehouses are
encountering three fundamental security issues, namely availability, integrity, and
confidentiality.
3.3.2 CIA tired in data security
The main challenges of cloud storage can be categorized into three aspects, namely
confidentiality, integrity, and availability (CIA). As mentioned earlier, the most
important factor in information systems is to protect the data against any unauthorized data modification, addition, or deletion. Since the data are moving through insecure media, considering the confidentiality before uploading the data to the cloud
servers is a necessity [44, 45]. ACID property to ensure the integrity has four contributions to the ability of a transaction to ensure data integrity. Cloud data can follow
ACID property to guarantee the integrity and confidentiality. For better understanding of these four qualities, it should be noted that ACID is an acronym for atomicity, consistency, isolation, and durability. In summary, atomicity is a transaction in a
situation to exhibit all or none of the treatments. In this regard, consistency is based
on the state of the data before or after the transaction is processed. Next property is
the isolation that is related to the transaction permitted to run at the same moment.
Any transaction running in parallel has the isolation property in the absence of any
concurrency. Finally, durability refers to the influence of the success or failure on
a processing transaction. There are many challenges in cloud data security that are
related to the four above-mentioned properties. In fact, when the security parameters
or VM configuration are described incorrectly, the multi-tenant nature of the cloud
significantly impresses the integrity and conditionality; in addition, the increased
number of users will increase security risks in the cloud. Unfortunately, these two
aspects are not enough to protect data in the cloud. One of the important goals in
cloud services is to provide the clients with excellent availability. In the field of
cloud availability, we should consider not only the software aspect of data, but also
the hardware aspect of data for authorized users. However, there are many various
methods to violate the availability of services including system errors, hardware and
software constraints, and malicious attacks from outside.
As a result, we conclude although data confidentiality is important, two other factors have more importance. In some cases, cloud service providers do not provide
13
H. Tabrizchi, M. Kuchaki Rafsanjani
cryptographic protection for stored data. For example, Microsoft One Drive does not
provide any encryption services to assign data confidentiality.
3.3.3 Metadata
In simple terms, metadata means data about data. Metadata contains confidential
and sensitive information, and by taking into account the importance of cloud services, it plays a much more important role and is becoming more complex. In fact,
metadata includes information related to data events, something was done, where it
was done, the file type and the format of the data, etc. The metadata contains valuable information that can be exploited by attackers. However, organizations use the
data in metadata to extract new business values from the information. Furthermore,
metadata includes confidential and sensitive information so it is very important to
use appropriate encryption mechanism to make these data secure. Unfortunately,
encryption only hides the data of massage, not the metadata of communication [46,
47]. An efficient way to protect this sensitive content against abusing is to employ
virtual private networks (VPN) that will guarantee data privacy and metadata
confidentiality.
3.4 Application security
One of the most important and vulnerable areas of information security is software
application security. Most of the applications have different platforms, frameworks,
and various types of vulnerabilities [48, 49]. One of the most important challenges in
cloud computing security is the vulnerabilities in the application security aspect. In
this regard, it should be considered that the software application has a million lines
of programming codes written by different programmers in different programming
languages and each has its own vulnerabilities. Since the developers are responsible for dealing with cloud application security, they need to understand the security aspects of cloud application programming and networking before developing
a software application. As discussed in detail in above, to define cloud application
security requirements with regard to data, a developer needs to focus on some areas
like encryption identity management services, authentication services, and identity
and access management services. However, in this section, we discuss the different
types of cloud application security issues. Nowadays, many application developers
use programming languages with default functions and classes having various vulnerabilities. For example, a programmer needs to know the security aspects of the
web-developing languages like HTML/CSS/PHP/JS to mitigate injection masked
code. From another point of view, SQL injection attacks abuse the back-end application weaknesses. The Open Web Application Security Project (OWASP) targets
aspects like back-end security and development hardening and testing. Additionally,
by taking into account the security issue in cloud applications, trust mechanism in
web-based business services plays a critical role in protecting sensitive information.
Unfortunately, these web-based services create some opportunities for malicious
attackers.
13
A survey on security challenges in cloud computing: issues,…
Generally, to perform tasks over the Internet, one of the most commonly used
methods is web applications, but the security aspect of web application vulnerabilities has faced a wide variety of shortfalls. In fact, hackers find some ways to insert
malicious executable codes into legitimate traffic sent to an endpoint. This process
is called code injection. Furthermore, similar to code injection, the cross-site scripting also provides some ways to insert malicious executable codes. However, its
difference is that it is involving scripts. As a result, lousy programming of things
like boundaries, exceptions, and credentials can make web applications vulnerable.
Sometimes, administrative issues cause configuration failures or lead to incomplete
component updates. As a result, special programming languages are designed in a
way making it harder to ensure them. The security of web application also complicates other challenges and causes a lot of problems like Internet service security
issues.
In addition to security problems in applications, operating systems (OSs) also
play an important role in the security of the cloud [50]. There is a relationship
between an application program and its operating system. In fact, the operating system is defined as an application which is run on a computer and also responsible for
the management and control of all the resources (memory, hard drives, monitors,
etc.) running different applications at the same time and sharing the tasks among
themselves. Cloud computing utilizes many virtual machines and different kinds of
servers in different networks and operating systems. This brings in many security
challenges and vulnerabilities on different operating systems used in cloud computing, such as desktop OS, server OS, network OS, and smartphone OS.
3.5 Network
Since cloud computing has been significantly dependent on the network, it has faced
a major challenge called network security. In fact, the main similarity between network security and cloud security is an evolving sub-area of computer security, network security, and information security. In the real world, networks encounter many
security challenges. As a result, network administrators must take appropriate security policies and use preventive mechanisms and services to protect data and cloud
infrastructure [51]. Unfortunately, network security has encountered significant connection availability threats such as the denial of service (DoS), distributed denial of
service (DDoS), flooding attack, and Internet protocol vulnerabilities. One of the
most effective and common methods to prevent these threats is to employ firewalls.
In the cloud, to check the safety of data, they are exchanged among the end users,
servers, and routers in cyberspace. Firewall-as-a-service (FWaaS) offers the same
protection as traditional firewalls. However, when a service is hosted in the cloud, it
means that it is available in all places on any device [52]. Since FWaaS is cheaper,
more efficient, and more flexible than traditional firewalls, it is a beneficial choice
for any company concerned about network security. Generally, using firewalls is not
a perfect way to defend cloud systems against threats but a strong firewall can reduce
vulnerabilities and branches. In simple terms, a firewall can block backdoor access
via a Trojan, but cannot tackle viruses, worms, and other malware. For this reason,
13
H. Tabrizchi, M. Kuchaki Rafsanjani
it is necessary that a firewall interacts with other systems [53]. In comparison, a firewall only analyzes packet headers and implements policies based on protocol type,
secure address, destination address, and secure port while intrusion detection system (IDS) detects and logs any malicious access to the network. IDS is designed
not only to prevent attacks, but also to log useful data for future security analyses.
In addition, the intrusion prevention system (IPS) is a network tool preventing any
malicious access to the network. IPS is designed not only to detect and log attacks,
but also to prevent malware or other types of intrusions. Eventually, it is worth noting that network security needs a broader overview which can be comprehensively
included in this survey. Therefore, it is suggested to refer to other specialized papers
for more information.
4 Security attacks and threats in cloud computing
The infrastructure of cloud computing with a great deal of hardware and software
components suffers from various security issues arising from the existing and new
threats. In the context of computer security, anything that has the potential to cause
serious damage to a computer system is called a threat. In other words, threats are
able to lead attacks on computer systems, networks, and other communication infrastructures. Threats can include everything from viruses, trojans, back doors to outright attacks from hackers. Due to the fact that each kind of public, private, or hybrid
cloud provides a flexible model for simplified management and cost efficiency, a privacy of data and security of software becomes considerable growing concerns.
4.1 Threat model and compromised attribute
Cloud computing provides many advantages, such as speed and efficiency via
dynamic scaling. But it also raises a host of concerns about security threats, such as
data breaches, human error, malicious insiders, and DDoS attacks. A threat model,
or threat risk model, is a process that reviews the security of any web-based system,
identifies problem areas, and determines the risk associated with each area. Threat
model considered identifying steps in the process such as identify security objectives, identify threats, and identify vulnerabilities. In fact, threat models are a systematic and structured way to identify and mitigate security risks in systems. Preeti
[54] presents a threat model for the attacks from one VM to another VM. In fact, two
VMs in the same tenant or different tenant with the same physical server is able to
become a victim of the attacks. Moreover, a malicious tenant user is able to set up an
attack by generating traffic floods with ICMP/UDP packets having a spoofed source
address and also it can exhaust the resources of the server at the virtualization layer.
STRIDE is a model of threats developed by Praerit Garg and Loren Kohnfelder at
Microsoft [55] for identifying computer security threats and provides an overview of
threats in a given system by categorizing them into six categories (spoofing, tampering, repudiation, information disclosure, denial of service, and elevation of privilege). Each category of the STRIDE captures individual features of the attacks that
13
A survey on security challenges in cloud computing: issues,…
pose a particular type of threat. In fact, the STRIDE threat model categorizes the
threats regarding the result or effect of their realization. The STRIDE threat model
has been captured the high-level view of the threats posed. Furthermore, this survey
extends the threat classification to the cloud component level advanced.
4.1.1 Spoofing
The act of disguising a communication from an unfamiliar source as being from a
known trusted source is called spoofing. In fact, spoofing aims to gain access to a
target’s personal information, spread malware through infected links or attachments,
bypass network access controls, or redistribute traffic to conduct a denial-of-service
attack [56]. Spoofing is able to apply to emails and websites with a lot of technical
aspects, such as a computer spoofing an IP address, or domain name system (DNS)
server. Since IP spoofing is not able to be prevented, measures can be taken to prevent spoofed packets from infiltrating a network. A well-known defense against
spoofing is ingress filtering which is a form of packet filtering. In addition, ingress
filtering usually implemented on a network edge device that examines incoming IP
packets and looks at their source headers. If the source headers on those packets do
not match their origin or they otherwise look fishy, the packets have to reject.
4.1.2 Tampering
Attackers may maliciously modify the data to interfere with operations. Unlike
spoofing, this threat directly modifies the system such as XML poisoning which is
able to change commands and codes to make the system malfunction [57]. One type
of data tampering is ransomware. In this attack, cybercriminals encrypt an organization’s data and demand payment of a ransom to obtain the decryption key. In fact, it
is vital that organizations are able to identify successful and unsuccessful attempts
to change critical files with a security control known as file integrity monitoring
(FIM). In other words, FIM is the process of examining critical files to know when
and how they changed. This system can compare the current state of a file to a
known, typically using a cryptographic algorithm to generate a mathematical value.
Due to a large amount of data stored by organizations today, monitoring all files
typically is not practical. For this reason, FIM systems generally are used to monitor
user identities, security settings, operating system and application files, configuration files, and encryption key stores. In addition, the monitoring of log files plays a
noticeable role in systems and applications which write data to logs and that log files
are frequently collected and stored in a separate management system.
4.1.3 Repudiation
When an application or system cannot adapt controls to properly track and log users’
actions, a repudiation attack is able to happen. This attack can be used to modify the
authoring information of actions executed by a malicious user in order to log the
wrong data to log files. Unfortunately, the repudiation attackers can deny actions
that cannot be proven due to the lack of ability to provide evidence [58]. In fact,
13
H. Tabrizchi, M. Kuchaki Rafsanjani
non-repudiation refers to the ability of a system to counter repudiation threats. In
cloud security, non-repudiation means a service that provides proof of the integrity
and origin of data which brings authentication with high reliability.
4.1.4 Information disclosure
Information can leak to unintended individuals due to malicious activities. There
are various ways information can leak from the system, such as VM configuration
stealing [59, 60] and scanning for open ports to discover services and their associated vulnerabilities [61]. There are two main types of disclosures that can happen
in cloud system: internal and external. An internal disclosure is when an employee
or administrator inadvertently makes private information public. This could happen
from lack of shredding, carelessness, mistakes, or not understanding the sensitivity
of information. An external information disclosure attack is aimed at acquiring system specific information about a provider, including software distribution, version
numbers, and patch levels. The acquired information might also contain the location of backup files or temporary files. To prevent disclosure of information attacks,
methods such as encryption and third-party authentication are used.
4.1.5 Denial of service
A denial-of-service attack is a security event that happens when an attacker prevents
legitimate users from accessing particular services or resources. In other words,
valid users are denied from the service due to malicious activities caused by cyber
attacks. DoS and DDoS attacks often use the vulnerability of how network protocols handle network traffic by transferring large numbers of packets to a vulnerable
network service from different Internet Protocol (IP) addresses to overwhelm the
service to deny legitimate users from accessing services or resources. To prevent
this kind of attack, various precautionary actions can be taken. Using multiple data
centers in different countries with a good load balancing system to distribute traffic
between them is a reasonable action to prevent DDoS attacks. Further action can
also be taken considering network firewalls and more specialized web application
firewalls. It is undeniable that software protection against DDoS attacks plays an
important role in the prevention of this kind of attack. These software protection
methods are able to monitor a number of incomplete connections that exist and
flushing them when the number reaches a configurable threshold value [62, 63].
4.1.6 Elevation of privilege
In this type of threat, an unprivileged user gains privileged access and thereby has
sufficient access to compromise or destroy the entire system. Elevation of privilege
threats includes those situations in which an attacker has effectively penetrated all
system defenses and become part of the trusted system itself, a dangerous situation
indeed. Vulnerabilities in the system can be exploited by attackers to bypass the system authentication, and various attack types can be used to exploit those vulnerabilities. One of the most common tactics an attacker could use to escalate privileges in
13
A survey on security challenges in cloud computing: issues,…
cloud environments is abuse overly permissive identity and access policies for cloud
users and services. These techniques involve policy creation and manipulation, profile changes, the ability to pass roles that may be in use and more [64]. To prevent
privilege escalation in the cloud, organizations can take a number of steps to help
prevent escalation of privilege attacks against their cloud environments. First, track
any vulnerability announcements from providers that may require an emergency
patch to prevent exploitation of flaws that could elevate privileges for attackers and
insiders. This should fall under the helm of vulnerability management programs
already in place. Next, perform regular audits of any policies and roles defined
within the cloud service environments by considering a penetration testing tool that
can be run against the considered environment to find out if any policy settings may
enable privilege escalation. Scanning tools from third-party providers can also be
used to scan cloud configurations for security issues. Finally, scan the environment
for exposed APIs using traditional network scanners and security query tools and
monitor cloud environments for suspicious network traffic or user activities.
Figure 5 illustrates the mappings of threats, attacks, and cloud components
in order to trace the existing vulnerabilities of the cloud components that provide
opportunity attacks. In addition, this figure categorizes threats based on the STRIDE
threat model and also categorizes attacks based on the OWASP attack classification.
STRIDE is an acronym that stands for six categories of security threat. Table 6
indicates that each category of threat aims to address one aspect of security. In
fact, threat modeling is a process by which potential threats, such as structural
Cloud Components
- Virtual Machine
- Web Server
- Operating System
- Application
- Data sources
Threats
Attacks
- Spoofing
- Tampering
- Repudiation
- Information Disclosure
- Denial of Service
- Elevation of Privilege
- Abuse Functionality
- Data Structure Attack
- Embedded Malicious Code
- Exploitation of Authentication
- Injection
- Path Traversal Attack
- Probabilistic Techniques
- Protocol Manipulation
- Resource Depletion
- Resource Manipulation
- Sniffing Attack
- Spoofing
Fig. 5 Classification of cloud component, threat, and attack
13
13
User spoofs the identify of another user by brute-forcing username/password credentials
A user performs injection attacks on the cloud application
Attackers commonly erase or truncate log files as a technique for hiding their tracks
A user is able to eavesdrop, sniff, or read sensitive data in a database
The cloud storage becomes too full
Authenticity
Integrity
Non-repudiability
Confidentiality
Availability
Authorization
Spoofing
Tampering
Repudiation
Information disclosure
Denial of service
Elevation of privilege
A user takes advantage of a buffer overflow to gain root-level privileges on a system
Examples
Desired property
Threat
Table 6 The STRIDE threat model
H. Tabrizchi, M. Kuchaki Rafsanjani
A survey on security challenges in cloud computing: issues,…
vulnerabilities, can be identified, enumerated, and prioritized—all from a hypothetical attacker’s point of view. The purpose of threat modeling is to provide defenders
with a systematic analysis of the probable attacker’s profile, the most likely attack
vectors, and the assets most desired by an attacker [65].
4.2 Cloud computing threats and risks
The Global Threat Report is an annual study published by the companies. This type
of report helps shine a light on current challenges and provides a useful roadmap for
your cloud security future. According Symantec’s inaugural Cloud Security Threat
Report (CSTR) 2019 [66], new forms of cross-cloud attacks are on the rise even as
malware and DDOS attacks. The report indicates that cloud malware injection is
ranked second among cloud threats after data breaches. With more workloads shifting to IaaS and PaaS, it becomes critical to take a consistent approach to discovering, monitoring, and remediating service misconfigurations, malware, and inappropriate access and privileges. In a lot of recent studies, great importance has been
given to threats such as data breaches, hacked interface and application program
interfaces, exploited system vulnerabilities, account hijacking, malicious insiders,
denial-of-service (DOS) attacks [67, 68].
4.2.1 Data breaches
The risk of a data breach is a top concern for cloud customers. In fact, a data breach
means releasing, viewing, stealing, or using protected or confidential information
like personal information such as credit card numbers, Social Security numbers for
any purpose which was not authorized to do. Unfortunately, there is not just one
control way to prevent data breaches. The most reasonable means for preventing
data breaches involve common sense security practices. This includes well-known
security basics, such as conducting ongoing vulnerability and penetration testing,
applying for proven malware protection, using strong passwords and consistently
applying the necessary software patches on all systems. Furthermore, in the event
of a successful intrusion into the environment, encryption will prevent threat actors
from accessing the actual data [69].
4.2.2 Hacked interface and application program interfaces
Application programming interface (API) also known as a user interface is the
way that provides access to the service. It is a program that you can operate from a
remote location. This interface provides key security that can be exploited because
some API’s give access to the cloud customer’s system and also every system has
specific vulnerabilities. For this reason, staying up to date with the latest patches for
software services is important. The difficulty is that this is all going on behind the
scenes [70]. The client may have been hacked and even may not know it, yet identify
what information was compromised, and the weak point in the cloud system that
allowed for the breach, is a crucial part of keeping a competitive edge in the world
13
H. Tabrizchi, M. Kuchaki Rafsanjani
today. A lot of the prevention can seem vague or unnecessary to keep data safe, but
it is vital to understand security and cloud providers.
4.2.3 Account hijacking
Cloud account hijacking is a process of stealing or hijacking a cloud account by an
attacker. Cloud account hijacking is a common tactic in identity theft schemes in
which the attacker uses the stolen account information to carry out the malicious or
unauthorized activity. In fact, when cloud account hijacking occurs, an attacker typically uses stolen credentials to impersonate the account owner. Using stolen credentials, attackers may gain access to critical areas of cloud computing services, compromising the confidentiality, integrity, and availability of those services. There are
a lot of effective steps that are able to keep data secure on the cloud such as require
multi-factor authentication and data security platforms. It is clear that several tools
exist that require users to enter static passwords as well as dynamic one-time passwords, which can be delivered via SMS or other schemes. For bolstered data theft
protection, companies should choose security platforms that extend to the cloud and
mobile. These types of data security platforms should include cloud security capabilities such as end-to-end encryption, application control, continuous data monitoring, and the ability to control or block risky data activity based on behavioral and
contextual factors involving the user, event, and data access type. This data-aware
and comprehensive approach enables organizations to manage cloud security risks
[41].
4.2.4 Malicious insiders
A malicious insider is a current or former employee or any business partner that has
or had authorized access to information system creates a threat if he or she intentionally misused that access to negatively impact the security and privacy aspects of
the information system. Malicious insider is a person that gains access to an organization’s network, system, or data and releases this information without permission
by the organization. There are many reasons an insider can be or become malicious
including revenge, coercion, ideology, ego, or seeking financial gain through intellectual property theft or espionage. Protecting against malicious insiders will depend
on organizations, systems, culture and business processes, and how well this is communicated and understood by staff [71]. A malicious insider’s system access and
knowledge of business processes can make them hard to detect. But practices can be
put in place to reduce the risk of a malicious insider in organizations such as controlling removable storage, controlling outbound emails and files, requiring strong
passwords, and using multi-factor authentication, access controls, etc.
4.2.5 Distributed denial‑of‑service attacks
DDoS attacks are able to make significant risks to cloud customers and providers,
including reputational damage and exposure of customer data. DDoS stands for
distributed denial of service which refers to the deployment of large numbers of
13
A survey on security challenges in cloud computing: issues,…
Internet bots, anywhere from hundreds to hundreds of thousands. These bots are
designed to attack a single server, network, or application with an overwhelming
number of requests, packets, or messages, thereby denying service to legitimate
users such as employees or customers [51, 72]. To prevent this type of attack, the
provider needs a battle plan, as well as reliable DDoS prevention and mitigation
solutions. In fact, the provider needs an integrated security strategy that protects
all infrastructure levels. Integrated security strategies such as develop a denialof-service response plan, secure network infrastructure, and maintain strong network architecture. Threat detection is one of the most efficient ways to prevent
the attack. Denial of service can come in multiple forms, and it is critical to recognize its visual indication. Any dramatic slowdown in network performance or
an increase in the number of spam emails can be a sign of an intrusion. These
should be addressed as soon as they are noticed, even if deviations do not look
that important at first. Businesses also need to understand their equipment’s capabilities to identify both network-layer and application-layer attacks with ISP, data
center, or security vendor to get advanced protection resources.
4.3 Attack in the cloud
It is undeniable that cloud computing aims to provide great deals of computing
resources over the Internet. While cloud computing models are full of advantages, this valuable phenomenon susceptible to both inside and outside attacks.
For this reason, cloud developers improve their knowledge about key vulnerabilities, the most common types of attacks and security measures in the cloud. Due
to a noticeable relationship between threats and attacks, this survey presents a
top-down categorization of attack based on the OWASP regarding attack characteristics. In the following, each attack described in detail.
4.3.1 Abuse functionality
Abuse of Functionality is an attack method using the own features and functionality of any aspect of computing to attack itself or others. For example, one infrastructure that provides services in the cloud environment without the authentication method might allow any users (including the attacker or real user) to utilize
the cloud computing resources to launch malicious attacks. In fact, the abuse of
an application’s intended functionality to perform an undesirable outcome called
abuse of functionality. These attacks have various types of results such as consuming resources, circumventing access controls, or leaking information. In addition, most of the time the abuse of functionality attacks uses a combination of
other types of attacks such as denial-of-service attacks, protocol exploitation,
application flaws, stealing or modifying VM configuration and launching a malicious VM [73, 74].
13
H. Tabrizchi, M. Kuchaki Rafsanjani
4.3.2 Data structure attack
Data structure attacks exploit characteristics of the system by exploiting the existing
vulnerabilities in data structures related to the process of system management. In
addition, attackers are able to access the system data directly and encourage a violation of normal usage by running the attacks like reference manipulation, attacking
shared memory and buffer overflow attacks. In fact, one of the common software
coding mistakes that provide an opportunity for an attacker to obtain access to the
system is a buffer overflow. To effectively alleviate buffer overflow vulnerabilities, it
is vital to understand buffer overflows, their possible dangers and other techniques
used to successfully exploit these vulnerabilities [75, 76].
4.3.3 Embedded malicious code
Each application might contain code that becomes malicious. In fact, the malicious
code may subvert the security of the application in a noticeable way. There are various types of attacks that directly manipulate the system with malicious code including Trojan horse, trapdoor, timebomb, and logic bomb. It is always possible for a
developer to insert malicious code with the intent to subvert the security of an application at the present time or in the future [77]. In addition, one embedded malicious code will not be executed until the user executes the application with the malicious code [78]. In today’s world, cloud computing is interacting with its users using
applications based on frameworks and programming languages that suffer from significant vulnerabilities. For this reason, cloud computing witnessed the attacks that
cause VMs to escape where the attacker can access and manipulate the VM and
another component of the cloud.
4.3.4 Exploitation of authentication
It is undeniable that system identification and authentication mechanisms have to
deal with vulnerabilities to prevent exposing sensitive data. Moreover, these types
of attacks exposed administration and management interfaces, redundant user profiles, and improper authentication and authorization can allow attackers to exploit
backdoor vulnerabilities [79]. Due to the fact that in many of today’s cloud computing applications, web-based applications are commonplace among developer companies. In addition, web-based applications are prime candidates for authentication
brute force attempts.
4.3.5 Injection
Attackers can inject code or query into a program, or by injecting one or multiple
malware onto a computer in order to modify a database. A code injection attack
appears in different forms relying on the execution context of the application and
the location of the programming flaw that leads to the attack [80]. This type of
attack plays a noticeable role in system hacking or cracking, unauthorized access
13
A survey on security challenges in cloud computing: issues,…
to a system in order to gain information. Moreover, the most widespread injection
attacks among the other injection attacks are SQL injection and cross-site scripting
(XSS).
4.3.6 Path traversal attack
The main object of path traversal attack is access files and directories that are stored
outside the web-root folder. This attack accesses arbitrary files and directories stored
on the file system by manipulating variables that reference files with “dot-dot-slash”
sequences. In addition, this type of attacks tends to access critical system files
including application source code or configuration [81, 82]. However, path traversal
attack provides unauthorized access through shared folders to manipulate cloud settings such as allowing VM escape.
4.3.7 Probabilistic techniques
Probabilistic techniques refer to probability-based attacks. This kind of attack considers a probability that the attack would be successful, where other attack categories would either succeed or fail regarding reasonable reason. In fact, the attacker is
able to exploit weak cryptographic systems by using different statistical and analytical approaches [83]. There various types of probability-based attacks such as attacks
include bruteforce attack, side-channel attack, man in the middle attack, and misconfiguration of the client-side validation to bypass authentication.
4.3.8 Protocol manipulation
That network protocols are able to be vulnerable to well-known attacks such as
attacks include denial of service, exploiting application communication flaws and
modifying the contents of the XML information passed among the users and the
servers to discover the security of the target [84]. In fact, incorrect implementation
relating to the protocols leads to this type of attack by sending malformed messages
exploiting bugs in protocol implementations, and adversaries can crash or hijack
victims.
4.3.9 Resource depletion
Resource depletion attack is the attack that uses a compromised node involving in
generating more network traffic which consumes the energy of the nodes. In fact,
resource depletion attacks at the routing protocol layer, trying to disable networks by
exhausting the energy of the nodes. Attackers are able to exhaust any computational
resources like cloud resources, such as network bandwidth, memory, and other computing capabilities [85]. Due to the fact that the cloud provides scalability to deal
with the workload size, the cloud is still likely to suffer from resource depletion
types of attacks such as volume-based flooding protocol exploitations or exploiting
application communication flaws.
13
H. Tabrizchi, M. Kuchaki Rafsanjani
4.3.10 Resource manipulation
Resource manipulation focuses on the way that manipulates one or more
resources in order to violate the integrity with planned changes in systems like
cloud systems. This type of attack can change the availability of resources including files, applications, libraries, infrastructure, and configuration information and
also information integrity [86]. Moreover, attackers are able to break down the
data and resources of the cloud by using parameter tampering. In fact, parameter
tampering is one form of a web-based attack that aims to change certain parameters in the web page form field data without user authorization. There are diverse
kinds of resource manipulation attacks such as manipulating a direct object reference to access unauthorized data and also modifying the XML content information between the user to server communication.
4.3.11 Sniffing attacks
Sniffing attacks can capture network traffic using a sniffer. In fact, the sniffer is
an application that aims to capture network transmitted packets across networks.
Moreover, if security mechanisms are misconfigured, this type of attack is able
to collect sensitive data by sniffing network traffic or allowing remotely stored
user data in the cloud environment [87]. Sniffing attacks are divided into passive sniffing and active sniffing. The passive sniffing captures data communicating between the two parties, and active sniffing uses tools and techniques to find
information about the system. This kind of attack is able to reveal existing vulnerabilities and misconfiguration in the system. These attacks aim to obtain sensitive
information on the network by scanning for open ports to find services and any
vulnerabilities associated with these services. In addition, attackers are able to
sniff features, parameters, and profiles in order to bypass normal authentication
in a customer device. However, one of the reasonable methods that lead to good
prevention against a packet sniffer is encryption. Encryption provides security for
private data against malicious intruders by keeping devices safe on the network.
4.3.12 Spoofing
In the area of network security, and in particular cloud security, a spoofing attack
is a set of situations in which a person or program successfully spoofs another
to gain an illegitimate advantage such as spoofing metadata by impersonating a
trusted email sender, DNS spoofing, IP spoofing, and phishing [88, 89]. In addition, DDoS attacks often employ spoofing in order to overwhelm a target with
traffic while masking the identity of the malicious source, preventing mitigation
efforts. However, this attack is able to conduct “cross-site request forgery” by
forcing “the user’s browser” to transmit an unauthorized command, such as forged
HTTP request, forcing the user to execute malicious actions on a web application.
13
A survey on security challenges in cloud computing: issues,…
5 Cloud security issues in the future
Cloud computing is an emerging paradigm that involves all the basic components
of computing such as end-user machines, communication networks, access management systems, and cloud infrastructures. In addition, with the emergence of
new phenomena such as the 5G Internet, Internet of Things (IoT), and smart cities, the role of cloud computing will be more vital for processing and storing
more information than ever before. The heterogeneity of the modern enterprise
environment has added a broader set of vulnerabilities and security concerns. In
recent years, organizations in the dark about how much and where data and workloads reside, making it harder to identify and mitigate mounting security risks.
Without a clear picture into the cloud infrastructure, security organizations are
grappling with issues from data duplication to the inability to identify threats in a
timely manner, with a loss of control over data access and the protection to meet
regulatory compliance. To achieve comprehensive cloud security, the data and
cloud infrastructure must be protected against known/unknown attacks across all
cloud components. There are several research gives her effort to solve the security
problems in a cloud environment. But, still there are many open issues are present
that is needed to be solved for providing a secure cloud infrastructure. The security issues related to cloud communication, network, data privacy, application,
and web services are some traditional issues that are present at the beginning of
cloud computing. Security issues that emerge due to multi-tenancy, virtualization, and shared pool resources are innovative security issues. In a cloud computing environment, several services and resources are available, but security level
of the resources depends upon the sensitivity and value level of the resource. The
privacy of the computation is open issue in cloud computing. In the storage, most
of the data are in an encrypted form. But, in the storage all the operations are
not performed over the encrypted data. Most of the operations required plain text
data during computation. The memory assigned to the within or outside processor
used for storing temporary data may be the target of attack. Therefore, research
endeavors in this respect to find a broad solution that provides privacy during
computation time. The cloud computing also needs a security solution against
insider threat. Many solutions are available and still applicable to the cloud. But,
the available solutions are not sufficient to solve the insider threat. In these phenomena, identification of the insider attack in cloud computing is an open area of
research. In this scenario, an indicator is developed that helps to find the insider
attacks. This indicator will increase the potential of securing the cloud system.
Similarly, another open issue, to identify who is the normal user and who is the
malicious user, still has a problem in a cloud environment. A growing number of
security platforms have incorporated AI and machine learning to automate tasks
and bring a higher level of intelligence to identify insider or outsider attack. This
includes user behavior analytics, used to identify potential security risks by establishing a usage baseline over time to identify abnormal cloud activity. Too many
companies are not acknowledging the perception gap in cloud security and are
vastly underestimating today’s threats, leaving themselves vulnerable to cloud
13
H. Tabrizchi, M. Kuchaki Rafsanjani
account compromises and data exposures that pose substantial reputational and
financial risk. Investment in cloud cyber security platforms that leverage automation and AI to supplement limited human resources is a clear way to automate defenses and enforce data governance principles. Automating the compilation and modeling of existing network data using behavioral analytics not only
helps organizations more readily identify and classify potential threats, and it also
makes them more efficient.
6 Conclusion
Cloud services are now a vital part of corporate life, bringing a momentous opportunity to accelerate business through their ability to quickly scale, allowing us to
be agile with our resources, and providing new opportunities for collaboration. In
fact, cloud brings many benefits to companies, organizations, and even countries.
Despite bringing several advantages, the cloud still is vulnerable to many security
challenges. This is why, security is the major challenge in the adoption of the cloud.
The customer and vendors are well aware of security threats. In other words, the
main purpose of the current study is to present all possible security challenges in
the cloud computing environment and provide appropriate solution to resolve these
issues. In fact, this research attempted to show various security challenges, vulnerabilities, attacks, and threats that hamper the adoption of cloud computing. Our
paper provided a survey on cloud security issues and challenges that arise from the
unique characteristics of the cloud. A generalized view of these issues has been presented here to enhance the importance of understanding the security flaws of the
cloud computing framework and devising suitable countermeasures for them. From
this line of research, we propose a review of recent security frameworks in terms of
reducing vulnerabilities in order to prevent possible attacks. Throughout the article,
we present a series of documented policies, procedures, and processes that define
the secure management way in the cloud environment in order to reduce risk and
vulnerability and increase confidence in an ever-connected world. These issues
encompass the security of data and services on cloud platforms. We categorize security challenges and perform a comparative analysis of security issues and the countermeasures suggested to cope with these issues.
References
1. Subramanian N, Jeyaraj A (2018) Recent security challenges in cloud computing. Comput Electr
Eng 71:28–42
2. Mell P, Grance T (2018) SP 800-145, The NIST Definition of cloud computing | CSRC (online)
Csrc.nist.gov. https​://csrc.nist.gov/publi​catio​ns/detai​l/sp/800-145/final​. Accessed 11 Dec 2018
3. Xu X (2012) From cloud computing to cloud manufacturing. Robot Comput Integr Manuf
28(1):75–86
4. Pippal SK, Kushwaha DS (2013) A simple, adaptable and efficient heterogeneous multi-tenant database architecture for ad hoc cloud. J Cloud Comput Adv Syst Appl 2(1):5
13
A survey on security challenges in cloud computing: issues,…
5. Shi B, Cui L, Li B, Liu X, Hao Z, Shen H (2018) Shadow monitor: an effective in-VM monitoring
framework with hardware-enforced isolation. In: International Symposium on Research in Attacks,
Intrusions, and Defenses. Springer, Berlin, pp 670–690
6. Bhamare D, Samaka M, Erbad A, Jain R, Gupta L, Chan HA (2017) Optimal virtual network function placement in multi-cloud service function chaining architecture. Comput Commun 102:1–16
7. Alzahrani A, Alalwan N, Sarrab M (2014) Mobile cloud computing. In: Proceedings of the 7th Euro
American Conference on Telematics and Information Systems (EATIS’14)
8. Deka GC, Das PK (2018) Application of virtualization technology in IaaS cloud deployment model.
In: Design and Use of Virtualization Technology in Cloud Computing: IGI Global, pp 29–99
9. Oracle.com (2018) The Oracle and KPMG Cloud Threat Report 2018 | Oracle (online). https​://
www.oracl​e.com/cloud​/cloud​-threa​t-repor​t.html. Accessed 11 Dec 2018
10. Hashem IAT, Yaqoob I, Anuar NB, Mokhtar S, Gani A, Khan SU (2015) The rise of “big data” on
cloud computing: review and open research issues. Inf Syst 47:98–115
11. Roman R, Lopez J, Mambo M (2018) Mobile edge computing, fog et al.: a survey and analysis of
security threats and challenges. Future Gener Comput Syst 78:680–698
12. Ramachandra G, Iftikhar M, Khan FA (2017) A comprehensive survey on security in cloud computing. Proc Comput Sci 110:465–472
13. Csrc.nist.gov (2018) SP 500-299 (DRAFT), NIST Cloud Computing Security Reference Architecture | CSRC (online). https​://csrc.nist.gov/publi​catio​ns/detai​l/sp/500-299/draft​. Accessed 11 Sept
2018
14. Yu S, Wang C, Ren K, Lou W (Mar 2010) Achieving secure, scalable, and fine-grained data access
control in cloud computing. In: Proceedings of the IEEE INFOCOM
15. Sgandurra D, Lupu E (2016) Evolution of attacks, threat models, and solutions for virtualized systems. ACM Comput Surv 48(3):1–38
16. Kaur M, Singh H (2015) A review of cloud computing security issues. Int J Adv Eng Technol
8(3):397–403
17. Kumar PR, Raj PH, Jelciana P (2018) Exploring data security issues and solutions in cloud computing. Proc Comput Sci 125:691–697
18. Khalil I, Khreishah A, Azeem M (2014) Cloud computing security: a survey. Computers 3(1):1–35
19. Bashir SF, Haider S (Dec 2011) Security threats in cloud computing. In: Proceedings of the International Conference for Internet Technology and Secured Transactions, pp 214–219
20. Ryan MD (2013) Cloud computing security: the scientific challenge, and a survey of solutions. J
Syst Softw 86(9):2263–2268
21. Wang C, Wang Q, Ren K, Lou W (Mar 2010) Privacy-preserving public auditing for data storage
security in cloud computing. In: Proceedings of the IEEE INFOCOM
22. Singh S, Jeong Y-S, Park JH (2016) A survey on cloud computing security: issues, threats, and solutions. J Netw Comput Appl 75:200–222
23. Khalil IM, Khreishah A, Azeem M (2014) Cloud computing security: a survey. Computers
3(1):1–35
24. Ahmed M, Litchfield AT (2018) Taxonomy for identification of security issues in cloud computing
environments. J Comput Inf Syst 58(1):79–88
25. Fotiou N, Machas A, Polyzos GC, Xylomenos G (2015) Access control as a service for the Cloud. J
Internet Serv Appl 6(1):11
26. Sumitra B, Pethuru C, Misbahuddin M (2014) A survey of cloud authentication attacks and solution
approaches. Int J Innov Res Comput Commun Eng 2(10):6245–6253
27. Fernandes DA, Soares LF, Gomes JV, Freire MM, Inácio PR (2014) Security issues in cloud environments: a survey. Int J Inf Secur 13(2):113–170
28. Subashini S, Kavitha V (2011) A survey on security issues in service delivery models of cloud computing. J Netw Comput Appl 34(1):1–11
29. Zhang Y, Chen X, Li J, Wong DS, Li H, You I (2017) Ensuring attribute privacy protection and fast
decryption for outsourced data security in mobile cloud computing. Inf Sci 379:42–61
30. Abbas H, Maennel O, Assar S (2017) Security and privacy issues in cloud computing. Springer,
Berlin
31. TechRepublic (2018) Building Trust in a Cloudy Sky (online). https​://www.techr​epubl​ic.com/resou​
rce-libra​ry/white​paper​s/build​ing-trust​-in-a-cloud​y-sky/. Accessed 11 Sept 2018
32. Basu S et al (2018) Cloud computing security challenges and solutions—a survey. In: Proceedings
of the IEEE 8th Annual on Computing and Communication Workshop and Conference (CCWC), pp
347–356
13
H. Tabrizchi, M. Kuchaki Rafsanjani
33. Dzombeta S, Stantchev V, Colomo-Palacios R, Brandis K, Haufe K (2014) Governance of cloud
computing services for the life sciences. IT Prof 16(4):30–37
34. Butun I, Erol-Kantarci M, Kantarci B, Song H (2016) Cloud-centric multi-level authentication as a
service for secure public safety device networks. IEEE Commun Mag 54(4):47–53
35. Saevanee H, Clarke N, Furnell S, Biscione V (2015) Continuous user authentication using multimodal biometrics. Comput Secur 53:234–246
36. Khalil I, Khreishah A, Azeem M (2014) Consolidated identity management system for secure
mobile cloud computing. Comput Netw 65:99–110
37. Faber T, Schwab S, Wroclawski J (2016) Authorization and access control: ABAC. In: McGeer R,
Berman M, Elliott C, Ricci R (eds) The GENI book. Springer, Berlin, pp 203–234
38. Khan MA (2016) A survey of security issues for cloud computing. J Netw Comput Appl 71:11–29
39. Cai F, Zhu N, He J, Mu P, Li W, Yu Y (2018) Survey of access control models and technologies for
cloud computing. Clust Comput 22(S3):6111–6122
40. Joshi MP, Joshi KP, Finin T (2018) Attribute based encryption for secure access to cloud based
EHR systems. In: Proceedings of the International Conference on Cloud Computing
41. Indu I, Anand PR, Bhaskar V (2018) Identity and access management in cloud environment: mechanisms and challenges. Eng Sci Technol Int J 21(4):574–588
42. Mohit P, Biswas G (2017) Confidentiality and storage of data in cloud environment. In: Proceedings
of the 5th International Conference on Frontiers in Intelligent Computing: Theory and Applications.
Springer, Berlin, pp 289–295
43. Khan SI, Hoque ASL (2016) Privacy and security problems of national health data warehouse: a
convenient solution for developing countries. In: Proceedings of the IEEE International Conference
on Networking Systems and Security (NSysS), pp 1–6
44. Tang J, Cui Y, Li Q, Ren K, Liu J, Buyya R (2016) Ensuring security and privacy preservation for
cloud data services. ACM Comput Surv (CSUR) 49(1):13
45. Islam MA, Vrbsky SV (2017) Transaction management with tree-based consistency in cloud databases. Int J Cloud Comput 6(1):58–78
46. Ku C-Y, Chiu Y-S (2013) A novel infrastructure for data sanitization in cloud computing. In: Diversity, Technology, and Innovation for Operational Competitiveness: Proceedings of the 2013 International Conference on Technology Innovation and Industrial Management, pp 3–25
47. Singh HJ, Bawa S (2018) Scalable metadata management techniques for ultra-large distributed storage systems—a systematic review. ACM Comput Surv (CSUR) 51(4):82
48. Sehgal NK, Bhatt PCP (2018) Cloud computing concepts and practics. Springer
49. Prokhorenko V, Choo K-KR, Ashman H (2016) Web application protection techniques: a taxonomy.
J Netw Comput Appl 60:95–112
50. Shin S et al (2014) Rosemary: a robust, secure, and high-performance network operating system. In:
Proceedings of the 2014 ACM SIGSAC Conference on Computer and Communications Security.
ACM, New York, pp 78–89
51. Somani G, Gaur MS, Sanghi D, Conti M, Buyya R (2017) DDoS attacks in cloud computing: issues,
taxonomy, and future directions. Comput Commun 107:30–48
52. Sattar K, Salah K, Sqalli M, Rafiq R, Rizwan M (2017) A delay-based countermeasure against the
discovery of default rules in firewalls. Arab J Sci Eng 42(2):833–844
53. Iqbal S, Kiah ML, Dhaghighi B, Hussain M, Khan S, Khan MK, Choo KKR (2016) On cloud security attacks: a taxonomy and intrusion detection and prevention as a service. J Netw Comput Appl
74:98–120
54. Mishra P, Pilli ES, Varadharajan V, Tupakula U (2017) Intrusion detection techniques in cloud environment: a survey. J Netw Comput Appl 77:18–47
55. Kohnfelder L, Garg P (1999) The threats to our products. Microsoft Interface, Microsoft Corporation, New York, p 33
56. Tounsi W, Rais HJC (2018) A survey on technical threat intelligence in the age of sophisticated
cyber attacks. Comput Secur 72:212–233
57. Meinig M, Sukmana MI, Torkura KA, Meinel CJPCS (2019) Holistic strategy-based threat model
for organizations. Proc Comput Sci 151:100–107
58. Mokhtar B, Azab MJAEJ (2015) Survey on security issues in vehicular ad hoc networks. Alex Eng J
54(4):1115–1126
59. Tan Y, Wu F, Wu Q, Liao XJTJOS (2019) Resource stealing: a resource multiplexing method for
mix workloads in cloud system. J Supercomput 75(1):33–49
13
A survey on security challenges in cloud computing: issues,…
60. Hong JB, Nhlabatsi A, Kim DS, Hussein A, Fetais N, Khan KMJCN (2019) Systematic identification of threats in the cloud: a survey. Comput Netw 150:46–69
61. Haber MJ, Hibbert B (2018) Asset attack vectors. Apress, Berkeley, CA
62. Rai S, Sharma K, Dhakal D (2019) A survey on detection and mitigation of distributed denial-ofservice attack in named data networking. In: Sarma H, Borah S, Dutta N (eds) Advances in communication, cloud, and big data. Lecture notes in networks and systems, vol 31. Springer, Singapore
63. Bojović P, Bašičević I, Ocovaj S, Popović M (2019) A practical approach to detection of distributed
denial-of-service attacks using a hybrid detection method. Comput Electr Eng 73:84–96
64. Eldewahi AE, Hassan A, Elbadawi K, Barry BI (2018) The analysis of MATE attack in SDN based
on STRIDE model. In: Proceedings of the International Conference on Emerging Internetworking,
Data and Web Technologies, pp 901–910
65. Tuma K, Scandariato R (2018) Two architectural threat analysis techniques compared. In: Proceedings of the European Conference on Software Architecture. Springer, Berlin, pp 347–363
66. Symantec.com (2019) Cloud Security Threat Report (CSTR) 2019 | Symantec (online). https​://
www.syman​tec.com/secur​ity-cente​r/cloud​-secur​ity-threa​t-repor​t. Accessed 19 July 2019
67. Akshaya MS, Padmavathi G (2019) Taxonomy of security attacks and risk assessment of cloud computing. In: Peter J, Alavi A, Javadi B (eds) Advances in big data and cloud computing. Advances in
intelligent systems and computing, vol 750. Springer, Singapore
68. Subramanian N, Jeyaraj AJC, Engineering E (2018) Recent security challenges in cloud computing.
Comput Electr Eng 71:28–42
69. Tan CB, Hijazi MHA, Lim Y, Gani A (2018) A survey on proof of retrievability for cloud data
integrity and availability: cloud storage state-of-the-art, issues, solutions and future trends. J Netw
Comput Appl 110:75–86
70. Ghafir I, Jibran S, Mohammad H, Hanan F, Vaclav P, Sardar J, Sohail J, Thar B (2018) Security
threats to critical infrastructure: the human factor. J Supercomput 74(10):4986–5002
71. Yamin MM, Katt B, Sattar K, Ahmad MB (2019) Implementation of insider threat detection system
using honeypot based sensors and threat analytics. In: Future of Information and Communication
Conference. Springer, Berlin, pp 801–829
72. Osanaiye O, Choo K-KR, Dlodlo MJJON (2016) Distributed denial of service (DDoS) resilience in
cloud: review and conceptual cloud DDoS mitigation framework. J Netw Comput Appl 67:147–165
73. Alsmadi I (2019) Incident response. In: The NICE Cyber Security Framework, pp 331–346
74. Fernandes G, Rodrigues JJPC, Carvalho LF, Al-Muhtadi JF, Proença ML (2018) A comprehensive
survey on network anomaly detection. Telecommun Syst 70(3):447–489
75. Nashimoto S, Homma N, Hayashi Y, Takahashi J, Fuji H, Aoki T (2016) Buffer overflow attack with
multiple fault injection and a proven countermeasure. J Cryptogr Eng 7(1):35–46
76. Chen Z, Han H (2017) Attack mitigation by data structure randomization. In: Cuppens F, Wang
L, Cuppens-Boulahia N, Tawbi N, Garcia-Alfaro J (eds) Foundations and practice of security. FPS
2016. Lecture notes in computer science, vol 10128. Springer, Cham
77. Cohen A, Nissim N, Rokach L, Elovici Y (2016) SFEM: structural feature extraction methodology
for the detection of malicious office documents using machine learning methods. Expert Syst Appl
63:324–343
78. Sangeetha R (Feb 2013) Detection of malicious code in user mode. In: Proceedings of the International Conference on Information Communication and Embedded Systems (ICICES)
79. Lichtman M, Poston JD, Amuru S, Shahriar C, Clancy TC, Buehrer RM, Reed JH (2016) A communications jamming taxonomy. IEEE Secur Priv 14(1):47–54
80. Wu M, Moon YB (2017) Taxonomy of cross-domain attacks on cyber manufacturing system. Proc
Comput Sci 114:367–374
81. Bhagwani H, Negi R, Dutta AK, Handa A, Kumar N, Shukla SK (2019) Automated classification of
web-application attacks for intrusion detection. In: Lecture notes in computer science, pp 123–141
82. Chen M-S, Park JS, Yu PS (1996) Data mining for path traversal patterns in a web environment. In:
Proceedings of 16th International Conference on Distributed Computing Systems, pp 385–392
83. Murugan K, Suresh P (2018) Efficient anomaly intrusion detection using hybrid probabilistic techniques in wireless ad hoc network. Int J Netw Secur 20(4):730–737
84. Ghose N, Lazos L, Li M (2018) Secure device bootstrapping without secrets resistant to signal
manipulation attacks. In: Proceedings of the IEEE Symposium on Security and Privacy (SP), pp
819–835
85. Osanaiye O, Choo K-KR, Dlodlo M (2016) Distributed denial of service (DDoS) resilience in cloud:
review and conceptual cloud DDoS mitigation framework. J Netw Comput Appl 67:147–165
13
H. Tabrizchi, M. Kuchaki Rafsanjani
86. Zhang X, Zhang Y, Mo Q, Xia H, Yang Z, Yang M, Wang X, Lunand L, Duan H (2018) An empirical study of web resource manipulation in real-world mobile applications. In: Proceedings of the
27th Security Symposium (Security 18), pp 1183–1198
87. Coppolino L, D’Antonio S, Mazzeo G, Romano L (2017) Cloud security: emerging threats and current solutions. Comput Electr Eng 59:126–140
88. Gumaei A, Sammouda R, Al-Salman AMS, Alsanad A (2019) Anti-spoofing cloud-based multispectral biometric identification system for enterprise security and privacy-preservation. J Parallel
Distrib Comput 124:27–40
89. Vlajic N, Chowdhury M, Litoiu M (2019) IP Spoofing in and out of the public cloud: from policy to
practice. Computers 8(4):81
Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in published
maps and institutional affiliations.
13